Shaken not stirred: Comparative studies using 2D-Clinostat and Random Positioning Machine

摘要

In the ESA ground-based facility programme, clinostats and Random Positioning Machines (RPMs) have been applied to achieve simulated microgravity, while centrifuges served to provide hypergravity. The results within the programme and beyond, clearly demonstrate that device-specific operational modes have to be considered and discussed with respect to the induction of shear forces and in turn the usability of these devices as potential microgravity simulators: In the RPM, samples are rotated around two axes with random velocities and directions, while clinostats render a constant rotation around one axis. With the present review, we want to present an overview of the literature available dealing with the differences in the use of clinostats and RPMs. We also include an example, which clearly visualises the differences of freely moving particles in both the RPM and the clinostat. We conclude that clinorotation around one axis induces substantially less shear forces in comparison to random positioning. Therefore, fast-rotating clinostats provide more valid information and should be preferred for the simulation of microgravity in cellular experiments.